Chap. II. CIECliatNUTATION OF SEEDI.BJGS. fiY 



CHAPTER II. 



GeNEIIAL CONSIDKEATIONS ON THE MOVEMENTS AND GROWTH OJ 



Seedling Plants. 



Generality of the oircumnutating movement — Radicles, tlieir eironm- 

 nutation of service — Manner in which they penetrate the ground — 

 Manner in whiclr hypocotyls and other organs break through the 

 ground by being arched — Singular manner of germination in Megai-- 

 rliiza, &e. — Abortion of cotyledons— Ciroumnutation of hypocotyls 

 and epiootyls whilst still buried and arched — Thtir power of 

 straightening themselves — Bursting of the seed-co'its— Inherited 

 effect of the arching process in hypogeau hypocotyls— Circumnutii- 

 tioa of hypocotyls and epiootyls when erect — Cii cumnutation of 

 cotyledons — Pulvini or joints of cotyledons, duration of their 

 activity, rudimentary in Oxalis corniculata, their development — 

 Sensitiveness of O/tylodons to light and consequent disturbance of 

 their periodic movements — Sensitiveness of cotyltdsns to contact. 



The circumniitating movements of the several paxts 

 or organs of a considerable number of seedling plants 

 have been described in the last chapter. A list is here 

 appended of the Families, Cohorts, Sub-classes, &c.. 

 to which they belong, arranged and numbered ac- 

 cording to the classification adopted by Hooker.* 

 Any one who will consider this list will see that the 

 young, plants selected for observation, fairly represent 

 the whole vegetable series excepting the lowest 

 cryptogams, and the movements of some of the lattei 

 when mature will hereafter be described. As all the 

 seedlings which were observed, including ConiferS; 

 Cycads and Ferns, which belong to the most ancient 



• As given in the ' General System of Botany,' by Le Maout and 

 Decaisne, 1873. 



